Twenty-three subjects (12 thymoma, 11 thymic carcinoma) have enrolled in this clinical trial and received treatment with Avelumab. Twenty-two subjects are evaluable for response. Four (18%) partial responses have been observed. Immune-related adverse events (irAEs) of any grade were observed in 12 (52%) patients and included myositis (17%), sicca syndrome (13%), myocarditis and thyroiditis (9% each). irAEs were generally manageable and resolved with appropriate therapy. Low baseline B-cell counts correlated with clinical response and occurrence of some irAEs.